Electrical terminals locked into a connector housing are subject to retention strength performance issues, especially with the smaller size categories of terminals (e.g. less than 2.8 mm). These smaller terminals historically have used scaled down locking features, which inherently have reduced locking retention strength and allow excessive terminal float. An excessively floating terminal can stub during mating, resulting in the terminal pushing out, and/or terminal damage especially if the retention strength within the connector housing is low. Within the automotive industry, inadequately locked terminals which pull out or push out, are recognized as the second highest root cause for failure of electrical connector systems within the vehicle warranty period.
Electrical connectors typically comprise internal cavities that are intended to accommodate electrical (male and/or female) terminals inserted from a rear face of the electrical connector. To ensure a well and safe functioning of the connector, it has to be ensured that the electrical terminals are locked in place within the electrical connector.
A solution known in the art includes providing a primary locking feature in form of a resilient retaining shoulder for preventing rearward withdrawal of the electrical terminals. The retaining shoulder, which is formed in the electrical connector, is designed to make a snap fit into a corresponding recess of the electrical connector at the end of the insertion of the electrical connector. A flexible retaining member is thereby disposed contiguously between the internal cavity and a slot, into which the retaining member can deflect. The retaining shoulder is formed on the face of the flexible retaining member that communicates with the internal cavity, such that on inserting the electrical terminal into the internal cavity, the retaining member first deflects in the slot before the retaining shoulder engages the recess of the electrical terminal.
In order to secure the primary locking, it is known, e.g. from U.S. Pat. No. 6,132,252, to insert an additional locking member built as a rail into the slot next to the retaining member as a secondary locking. The electrical terminal being fully inserted into the internal cavity and the primary locking being engaged, the locking member is inserted into the slot from a front face of the electrical connector according to a direction corresponding to the loading direction of the electrical terminal. The retaining member is thus prevented from being flexed away from the internal cavity, thereby firmly retaining the electrical terminal. If the electrical terminal is incompletely inserted into the internal cavity, the retaining member is maintained in a deflected position into the slot, such that the locking member cannot be mounted.
The secondary locking mechanism known in the art requires a locking member being inserted frontward of the electrical connector in the direction opposite to that of the insertion of the electrical terminal. However, the configuration of the electrical connector may be such that a frontward insertion of the locking member is not possible, e.g. because there is not enough space at the front face side. In addition, the retaining members in connectors used with smaller terminals may easily buckle, terminal tangs may bend, and secondary locking mechanism may provide limited additional strength due to packaging constraints with terminals smaller than 2.8 mm. These solutions to date have only met the minimum terminal retention requirements, in many cases, all with little to no performance margin.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.